See this post for my previous rantings in favour of Compact Flash:
http://www.cableforum.co.uk/board/sh...9&postcount=21
I would definately avoid anything that uses an obsolete card format like Smartmedia.
Next, unless I had a special reason, I would avoid any proprietary format like Memory Stick and xD. As with lens mounts, manufacturers like to lock users into their own brand.
Currently, this leaves only two formats - SD and CF. As mentioned above SD includes digital rights management (which I am not particularly fond of) and there is a
vast range of accessories that are CF compatible. Check out some of them
here. Did you know that you can plug a CF card into a PCMCIA slot using a simple passive adaptor that rearranges the pins? Also, with another passive adaptor, you can connect a CF card to an IDE slot so that it behaves just like a HDD - with no drivers!
IMHO there is only one logical choice and I always look for equipment that supports it.